Cherry tree (rootstock) named ‘King’

ABSTRACT

A new cherry tree variety suitable for use as rootstock.

Botanical designation: The present invention relates to a new Prunus cerasus L. cherry tree variety.

Variety denomination: The new plant has the varietal denomination ‘King’.

BACKGROUND OF THE INVENTION

This invention relates to a new and distinct variety cherry tree. In the field of plant genetics, researchers conduct an extensive and continuing plant-breeding program including the organization and asexual reproduction of orchard trees, and of which plums, peaches, nectarines, apricots, cherries, almonds and interspecifics are exemplary. It was against this background of activities that the present variety of cherry tree was originated and asexually reproduced in our experimental orchard.

PRIOR VARIETIES

Among the existing varieties of cherry trees, which are known to us, and mentioned herein ‘Maliga Emléke’ (not patented); ‘English Morello’ (not patented); ‘Gisela® 3’ (Test Name ‘GI 2091’, U.S. Plant Pat. No. 16,173), ‘Gisela® 5’ (Test Name ‘GI 148/2’, U.S. Plant Pat. No. 9,622), and ‘Gisela® 6’ (Test Name ‘GI 148/1’, U.S. Plant Pat. No. 8,954), ‘Clinton’ (U.S. Plant Pat. No. 30,538) , ‘Cass’ (U.S. Plant Pat. No. 30,553), ‘Lake’ (U.S. Plant Pat. No. 32,813), ‘Clare’ (U.S. Plant Pat. No. 32,852), ‘Crawford’ (U.S. Plant Pat. No. 30,473), ‘Hedelfingen’ (not patented); ‘Bing’(not patented); and ‘Montmorency’ (not patented)

ORIGIN OF THE VARIETY

‘King’ originated from a hand-pollinated cross performed in 1995 between two selections, ‘II 3(11)’ and ‘III 16(29)’ performed in Clarksville, Mich. The maternal parent ‘II 3(11)’ originated from a hand-pollinated cross performed in 1983 between the cultivars ‘English Morello’ and ‘Maliga Emléke’. The paternal parent ‘III 16(29)’ was derived from an open-pollinated seed of unknown origin collected in Romania in 1985. ‘King’ was originally designated by its field number, 26e12(61), and prior to advanced field testing it was named ‘King’.

The seedling that gave rise to ‘King’ was planted in Clarksville, Mich. in 1996 and was propagated asexually by cuttings in 1999 to provide materials for the first rootstock evaluations. ‘King’ rootstock was selected as promising based on initial trials planted in Clarksville, Mich. in 2002 with ‘Hedelfingen’ scion and in Prosser, Wash., planted in 2002 with ‘Bing’ scion. Meristem culture-derived rootstocks of ‘King’ were subsequently produced, budded with ‘Montmorency’ scion, and the trees were planted in Traverse City, Mich. in 2011 for further evaluation.

ASEXUAL REPRODUCTION OF VARIETY

Asexual reproduction of the ‘King’ cherry rootstock was achieved using the mother plant to obtain rooted liners using conventional softwood cutting procedures, and through meristem culture with commercial nurseries. Initially, liners were propagated from softwood cuttings in commercial greenhouses. A subset of these liners was used to establish a mother block in Clarksville, Mich. The remaining liners were sent to a nursery to make test trees of ‘King’ that were budded with the scion ‘Hedefingen’ and ‘Bing’. The resulting trees with ‘Hedelfingen’ and ‘Bing’ scion were planted in trials in Clarksville, Mich. and Prosser, Wash., respectively. A second set of liners was propagated from meristem culture. These ‘King’ liners were budded with ‘Montmorency’ scion to make trees for a trial in Traverse City, Mich. The living tissues (i.e. leaves, stems, buds, flowers and fruits) of the original mother block plants were observed to be identical to secondary and tertiary vegetatively propagated plants.

STATEMENT OF STABILITY

Asexual propagation as described has demonstrated that the combination of traits that characterize this tree are fixed and remain true to type through at least two successive propagation cycles.

SUMMARY OF THE INVENTION

‘King’ is particularly useful as a rootstock. ‘King’ cherry rootstocks result in smaller trees than standard ‘mahaleb’ and ‘mazzard’ rootstocks, with trees sizes similar to ‘Gisela® 6’. The rootstocks do not induce precocity as the other ‘Clinton’, ‘Cass’, ‘Lake’, ‘Clare’ and ‘Crawford’ rootstocks or ‘Gisela®’ rootstocks. ‘Montmorency’ trees on ‘King’ were observed to have high yields in mature orchards. Therefore, ‘King’ rootstock offers increased planting density without the associated crop load management issues associated with highly dwarfing precocious rootstocks. ‘King’ is suitable for standard nursery propagation practices for uniform liner production.

COMPARISON WITH PARENTS

The new cherry variety may be distinguished from its seed parent, ‘II 3(11)’ which was selected from a segregating progeny population that originated from a hand-pollinated cross performed in 1983 between the cultivars ‘English Morello’ and ‘Maliga Emléke’. The paternal parent ‘III 16 (29)’ was derived from an open-pollinated seed of unknown origin collected in Romania in 1985 and was also selected from a segregating progeny population. ‘King’ can be phenotypically distinguished from its parents by fruit color. For example, the fruit skin color for ‘King’ is RHS185A, in the greyed/purple group of the color chart. By comparison the skin color for ‘II 3 (11)’ is light red. The flesh color for ‘King’ is RHS26C, in the yellow group. By comparison the flesh color for ‘III 16 (29)’ is light red/purple.

COMPARISON WITH KNOWN RELATED CULTIVARS

The new cherry variety may be distinguished from known related cultivars, for example ‘Lincoln’, by a combination of several characteristics. First, the number of lenticels is medium for ‘Lincoln’ and few for ‘King’. The shape of the apex of vegetative bud is obtuse for ‘Lincoln’ and acute for ‘King’, the ratio of length to width of leaf blade is small for ‘Lincoln’ and medium for ‘King’, the flower pedicel length is 10 mm for ‘Lincoln’ and 20 for ‘King’, mature fruit shape is kidney for ‘Lincoln’ and flat spherical for ‘King’ among other traits.

TABLE 1 Comparative Data Table Characteristics ‘King’ Vigor - TCSA Similar to ‘Gi6’ Vigor - canopy Similar to ‘Gi6’ Precocity Low (Less than ‘Clare’, ‘Crawford’, ‘Lake’, ‘Clinton’ and ‘Gisela ® 3, 5 & 6’) Fruit size Similar to ‘Gi6’ Graft compatibility¹ Good (limited scions tested) Needs support No Root suckers + (few) Mid-winter cold stress Tolerant ¹Ratings are based on trees with ‘Bing’, ‘Hedelfingen’, and ‘Montmorency’ scions.

‘King’ cherry rootstocks result in smaller trees than standard ‘mahaleb’ and ‘mazzard’ rootstocks, with trees sizes similar to ‘Gisela® 6’. These rootstocks do not induce precocity as the other ‘Clinton’, ‘Cass’, ‘Lake’, ‘Clare’ and ‘Crawford’ rootstocks or ‘Gisela®’ rootstocks. Comparative yield data is not available for these rootstocks as yield data was only taken for those rootstocks that induced extremely precocious flowering. However, ‘Montmorency’ trees on ‘King’ were observed to have high yields in mature orchards. Therefore, this rootstock offers increased planting density without the associated crop load management issues associated with highly dwarfing precocious rootstocks.

BRIEF DESCRIPTION OF PHOTOGRAPHS

The accompanying photographs display flowers, leaves, and fruits from a self-rooted mother block tree at Clarksville, Mich. in April 2021.

FIG. 1 is a photograph of the flowers of ‘King’.

FIG. 2 is a photograph of a tree of ‘King’.

FIG. 3 is a photograph of fruit of ‘King’.

FIG. 4 is a photograph of the overall habit of ‘King’ growing in a hedgerow, taken after leaf drop in March 2022.

DESCRIPTION OF THE NEW VARIETY

The following is a detailed botanical description of the new variety of cherry tree, its flowers, foliage and fruit, as based on observations of various aged specimens grown in Clarksville, Mich. with color in accordance with The Royal Horticultural Society Colour Chart (R.H.S.), 2001 edition.

Measurement Details

-   Flowers:     -   -   Inflorescence height.—Measured from where the flower cluster             attaches to the branch to the most distal floral part.         -   Flower diameter.—Measured across the petals in mm.         -   Flower length.—Measured from the bottom of the pedicel to             the most distal flower point (mm).         -   Pedicel.—The stem of an individual flower. It is measured             from the attachment in the bud to the start of the perianth.         -   Peduncle.—A stalk supporting an inflorescence. In these             selections, the cherry flowers within a flower bud all start             at the same base and they the stalk separates into             individual pedicels supporting each flower.         -   Anther color.—Before the anther's dehisce, when they are             still bright yellow and plump.         -   Anther length.—Measured for the longest anther measured from             the top of the perianth tube.         -   Style.—Measured above the swelled ovary.

Characteristics

-   Tree:     -   -   Plant height.—Approx. 6 m.         -   Plant vigor.—Medium.         -   Plant habit.—Spreading.         -   Plant branching.—Strong.         -   Hardiness.—Cold resistant, drought/heat tolerance not             exhibited.         -   Scion compatibility confirmed.—‘Bing’, ‘Hedelfingen’,             ‘Montmorency’. -   One year old shoot:     -   -   Thickness.—5 mm.         -   Length of internode.—2.5 cm.         -   Pubescence.—Absent.         -   Relative number of lenticels.—Few.         -   Anthocyanin coloration of apex.—Absent.         -   Position of vegetative bud in relation to shoot.—Markedly             held out.         -   Shape of apex of vegetative bud.—Acute. -   Leaves:     -   -   Mature leaf arrangement.—Alternate.         -   Intensity of anthocyanin coloration of young leaf.—Weak.         -   Leaf blade shape.—Ovate.         -   Leaf blade ratio length to width.—Medium.         -   Leaf length (blade only).—7.7 cm.         -   Leaf width.—3.7 cm.         -   Leaf blade angle of apex.—Acute.         -   Leaf blade shape of base.—Obtuse.         -   Leaf blade shape of apex.—Acute.         -   Leaf blade incisions of margin.—Crenate.         -   Leaf blade depth of incisions of margin.—Shallow.         -   Leaf blade glossiness of upper side.—Medium.         -   Leaf blade pubescence of lower side.—Weak.         -   Upper surface color.—R.H.S. 137A.         -   Leaf upper surface texture/pubescence.—Smooth.         -   Leaf upper surface venation color.—R.H.S. 137B.         -   Leaf venation pattern.—Pinnate.         -   Lower surface color.—R.H.S. 137B.         -   Petiole.—Intensity of pubescence of upper side — weak.         -   Petiole.—Depth of groove — medium.         -   Leaf petiole length.—14 mm.         -   Leaf petiole diameter.—1.5 mm.         -   Leaf petiole color.—R.H.S. 59A.         -   Leaf.—Presence of nectaries — present.         -   Leaf.—Predominant number of nectaries — two.         -   Leaf.—Position of nectaries — base of leaf blade.         -   Nectary shape.—Reniform.         -   Leaf stipule length.—9 mm.         -   Leaf stipule width.—1.7 mm.         -   Leaf stipule shape.—Pointed.         -   Leaf stipule margin.—Serrated. -   Flowers:     -   -   Fragrance.—None.         -   Bloom date (50%).—Apr. 24, 2021.         -   Inflorescence diameter.—5 cm.         -   Flower diameter.—32 mm.         -   Petal arrangement.—Flat whorl.         -   Petal margin.—Smooth.         -   Petal texture.—Smooth.         -   Petal color when fully open (upper surface).—R.H.S 155D.         -   Petal color when fully open (lower surface).—R.H.S 155D.         -   Sepal shape.—Triangle.         -   Sepal apex.—Pointed.         -   Sepal margin.—Slightly serrated.         -   Sepal texture.—Slightly pubescent.         -   Sepal color upper.—R.H.S 138A.         -   Sepal color lower.—Both R.H.S 138B and 59A.         -   Flower pedicel length.—20 mm.         -   Flower pedicel diameter.—1 mm.         -   Flower pedicel texture.—Smooth.         -   Flower pedicel color.—Both R.H.S 59A and 138B.         -   Flower peduncle length.—3 mm.         -   Flower peduncle diameter.—3 mm.         -   Flower peduncle texture.—Smooth.         -   Flower peduncle color.—R.H.S 138B.         -   Pistils.—Number per flower — 1.         -   Style length.—11 mm.         -   Style color.—R.H.S 138D.         -   Stigma shape.—Round/indented.         -   Stigma color.—R.H.S 138D.         -   Stamen filament color.—R.H.S 155D.         -   Longest anther length.—11 mm.         -   Anther color.—R.H.S 20A.         -   Pollen color.—R.H.S 17C. -   Fruit:     -   -   Mature fruit shape.—Flat spherical.         -   Mature fruit height.—13 mm.         -   Mature fruit width 1.—19 mm.         -   Mature fruit width 2.—19 mm.         -   Mature fruit ratio height/width.—2.         -   Mature fruit weight.—5 g.         -   Mature fruit taste.—Sour.         -   Mature fruit skin color.—R.H.S. 185A.         -   Mature fruit flesh color.—R.H.S. 26C.         -   Stone color.—R.H.S. 164D.         -   Stone shape.—Spherical.         -   Stone number.—1.         -   Stone height.—8 mm.         -   Stone width 1.—7.5 mm.         -   Stone width 2.—6 mm.         -   Stone ratio height/width.—2.         -   Stone weight.—0.3 g.         -   Fruit stem length.—40 mm. -   Market use: Rootstock. 

I claim:
 1. A new and distinct variety of cherry tree named ‘King’, substantially as described and illustrated herein. 